SPERMATOGENESIS OF ASCARIS 44] 
also for those which do not, and which therefore must be quite 
different in origin and nature. While Meves and Korff use it to 
represent this yolk-forming material of nuclear origin, Benda, 
Duesberg and others use it to represent structures which they 
believe are wholly cytoplasmic in origin, aud give rise to the vari- 
ous connective tissus of the embryo. The authors just mentioned 
state that the mitochondria always take basic stains, though they 
do not arise in the nucleus. But Mayer, Romieu and other 
students of Ascaris spermatogenesis call the small, dense gran- 
ules found in the ‘perinuclear zone’ of the spermatid, and in the 
‘crown’ of the spermatozoon, mitochondria. But these granules 
not only take acid stains always, but they unquestionably arise 
in the nucleus. Besides, no one has yet found that they give 
rise to any yolk or embryonic tissue. They seem to be merely 
inert residua. 
Manifestly, therefore, the term ‘mitochondria’ is useless. Meves 
recognizes the inappropriateness of this name for the gran- 
ules in Ascaris just mentioned, and calls them ‘plastochondria’ 
because of their resemblance to the plastosome in all staining 
reactions, and their possible origin in it. 
I would suggest the name ‘karyochondria’ for the yolk-forming 
granules because of their close relation to the karyochromatin. 
It remains to be seen, I think, whether all inclusions in the cyto- 
plasm of sex cells of other forms referred to as ‘mitochondria’ 
cannot be identified with one or the other of these, the plasto- 
chondria or the karyochondria, for there is abundant evidence 
that both yolk-forming and organ-forming factors first arise in 
the nucleus and’ pass out into the cytoplasm, as will be shown 
later. 
Among the earlier students of Ascaris spermatogenesis, Van 
Beneden spoke of Meves’ plastochondria merely as ‘protoplasmic 
corpuscles,’ attributing no function whatever to them. Hert- 
_ wig figures them in the refringent vesicles, just before the matur- 
ation divisions, but he does not discuss them. Boveri found 
them in the egg, surrounding the male and female pronuclei. 
He called them ‘archoplasmic grains,’ but he attributed no sig- 
nificance to them. ‘Tretjakoff figures them scattered among the 
